It apparently is yes,or an old frame studded with saphires.Haven´t yet seen a clear enough picture but yes,after the appearance of the Ruby Peacock parure,there´s this new edition of an old parure.Wonderfull don´t you think?

The diadem worn by HRH Princess Margriet is the converted necklace of Queen Emma's grand saphire parure,a piece not seen for a long time,but beautifully converted into this marvel.

On this wonderful site http://www.royaldutchjewels.nl/Sapphire_Parure.htm you can see a close-up showing that the prongs from the 'new' sapphire tiara are remains from the wedding gift parure which has been broken up.
I always had the impression that Princess Margriet likes to wear blue, so it is great that there is another sapphire tiara which is not exclusively worn by Queen Beatrix.

she ahs worn a lot of jewllery throgh the years how much is her own jewllery is there any items with history and will they then go to the royal foundations?

All items belong in the Royal House Historical Collection Foundation.
At least all the jewelry worn in official functions,except for the minor
jewelry like brooches,ear-jewelry and such during visits in the country.

Wow, how unusual for her to wear a tiara at this ball. Maybe it was to mark the 30th edition.

She has always worn a tiara for this ball. But always one of the smaller ones like the aquamarine tiara or the Earth of Wheat tiara. But her daughter-in-laws have also attended sometimes but they have never worn a tiara apart from their Wedding Day.